Distributing-switch



G. THOMPSON.

DISTRIBUTING SWITCH. APPLICATION men MAYIO. 1919.

Patented Apr. 26, 1921.

/m/e/1f0/ Gearqe Thompson UNITED STATES PATENT OFFEQE.

GEORGE THOMPSON, OF MOUNT VERNON, NEW YORK, ASSIGNOB TO WESTERN ELEG-TRIO COMPANY, INCORPORATED, OF NEW YORK, N. Y., A. CORPORATION OF NEWYORK.

Application filed. May 10,

To all whom it may concern:

Be it known that I, GEORGE THOMPSON, a citizen of the United States,residing at Mount Vernon, in the county of VVestchester, State of NewYork, have invented certain new and useful Improvements inDistributing-Switches, of which the following is a full, clear, concise,and exact description.

This invention relates to automatic telephone exchange systems, and moreparticularly to the mechanical construction of a switch suitable for usein such systems.

An object of this invention is to provide a switch which shall be simplein construction and rapid in operation.

A feature of the invention is the use of mechanically operable contactsets individual to outgoing lines, the arrangement being such that thesecontact sets are moved out of the path of a moving contact-operatingelement when the line with which they are associated is in anon-selectable condition.

An additional feature of the invention is the provision of three movablecontact-operating members in fixed relation to one another. The switchis designed primarily for use as a hunting switch, and the peculiarangular relation between these three contactoperating members and thesets of contacts arranged for coeperation with them, is such thatwhichever contact operating member first reaches a line in the desiredcondition will operate the contacts of such line. As a result of thisarrangement fewer steps are necessary before a line in the desiredcondition can be seized.

A further advantage which may be obtained from the use of aswitch ofthistype is again due to the peculiar angular relation between thecontact sets and the contactoperating members. As a result of thisarrangement the outgoing lines will not be tested in a predeterminedorder, and therefore the apparatus associated with such out going lineswill receive approximately equal shares of the work' which is to bedistributed to them by the switch. I

The switch, as shown and described. is intended for use primarily as adistributing switch individual to a calling subscribers line. It isobvious, however, that a switch of this character is adapted to avariety of Specification of Letters Patent.

Patented Apr. 26, 192 1.

1919. Serial No. 296,180.

uscs, and the invention is, therefore, to be restricted only by theappended claims.

It is thought that the invention will be best understood from thefollowing detailed description, reference being had to the accompanyingdrawings. In the drawings, Figure 1 shows operat- 1ng circuits for aswitch embodying the features of the present invention, and Fig. 2 showssuch portions of an operating mechanism as are necessary to anunderstanding of the operation of the switch.

The mechanical construction of the switch will first be described.Referring now to Flg. 2, a shaft 1 is rotatably mounted on bearings ofany suitable character. Secured to said shaft and rotatable therewith isa yoke provided with three arms, 3, 4 and 5. The arms 3, 4 and 5 projectradially from the center of rotation and are spaced apart equal angulardistances. Since the three arms are spaced equally in the circumferenceof a circle, it is obvious ,that the distance between the arms is 120".FiXedly secured to the yoke 2 is a ratchet wheel 6, which may be rotatedin a counter-clockwise direction under the control of a resilient pawl,7, mounted on the armature 8 of a stepping magnet 9. Ten sets ofcontacts similar to the sets lndicated generally at 10 are spacedequally about the circumference of the circle. The contacts 10 arearranged in pairs and are operated by the action of cams 11 and 12carried by each of the arms 3, 4: and 5 respectlvely. Each set ofcontacts 10 is mounted on an arm 13, pivoted at 14 and arranged formotion in a vertical plane under the control of a magnet 15.

Briefly. the operation of the switch is as follows: When a call isinitiated, stepping magnet 9 will function in a self-interruptingcircuit to advance the contact operating members carried by the arms 3,1 and 5 respectively. The contacts sets 10 of all trunks, which are in abusy condition, will be drawn down out of the path of the movingcontact-operating elements due to the energization of their associatedmagnets 15, itbeing understood that there is a magnet 15 for each trunkat each subscribers switch. These magnets 15 function in multiple when aline is seized so that the trunk cannot be seized by the switch of anyother subscriber,

since the contact set associated with such "trunk at the othersubscribers switch will be out of the path of the movingcontact-operating element. As soon as a set of contacts is operated,which will occur as soon as the operating elements carried by one of thearms 3, 4; or 5, engage a contact set which is projecting into the pathof such elements, the circuit of stepping magnet 9 is opened and theswitch is brought to rest. Coincident to the operation of the set 10,the trunk cut-off relays 15 associated with such trunk at othersubscribers switches will function to remove all other contact sets outof possible engagement, thus rendering the trunk non selectable. Thepossibility of overthrow or reverse movement of ratchet wheel 6 iseliminated by the action of a holding pawl 17.

Since the contact sets are spaced equally about the circumference of thecircle, and are ten in number, it follows that the angular distancebetween adjacent contact sets is 36. The ratchet wheel 6 is designed tohave 60 teeth so that the contact-operating members will be advanced 6at each step of the ratchet wheel.

It will now be assumed that the various points about the circumferenceof the circle, described by the arms 3, 4 and 5 during rotation, atwhich-contact sets are located, are indicated by the letters A, B, C, D,E, F, G, H, M and N, respectively. It will further be assumed that atthe time a call is initiated the position of the various arms withrespect to these contact sets is as shown in the drawings. By recallingthat the contact sets are 36 apart and that the contact-operating armsare spaced 120 apart, it will be obvious that if contact arm 5 must beadvanced one step to operate the contacts at B then the contact arm 41will be one step. in advance of position M, and arm 3 will be threesteps in advance of position F. 4

VVhen the subscriber initiates a call the arms 3, 4c and 5 will beadvanced. If the trunk, whose associated contact set is located at B, isin a selectable condition, the contacts of such trunk will be operatedand the switch brought to rest in this position. However, if the contactset at B is. asso ciated with-a busy trunk, the switch will continue itsadvance and the neXt set of con: tacts to be tested will be that at E.The trunk associated with the contacts ofE will or will not be seized inaccordance with the idle or busy condition of such trunk. Provided thatthe contacts at E are those of a non-selectable trunk, arm 4- will makethe nexttest when it reaches position H. It will, therefore, be seenthat each succeeding test is made in a different sector of the circle.

When a contact set associated'with an idle trunk is found, the switch isbrought to rest and the members 11 and 12 operate the contacts of suchset. Upon completion of the conversation the switch is advanced onestep. For instance, if upon initiation of a call the subscribers line isextended to the trunk whose contacts appear at B, this step will bringarm 3 within 2 steps of the contact set at E. The step made upon releasewill then bring arm 3 within one step of the contact set at E, so thatupon initiation of a subsequent call the trunk, whose contact setappears at E, may be seized upon but one step of the switch. Aninspection of the draw ing will show that whenever the switch isreleased, regardless of which arm and which contact set was utilized,there will always be an arm within one step of a contact set andtherefore only one step will be necessary, upon a subsequent initiationof a call, to seize the trunk associated with such contact set, providedthat it be idle.

The operating circuits of the switch will now be described, referencebeing had to Fig. 1. When the subscriber, whose substation is indicatedat 18, removes his receiver from the switchhook, a circuit is completedfrom the grounded battery, upper winding of the line relay 19, outerupper armature of cutoff relay 20, then in series through the normallyclosed springs 21 associated with the various outgoing lines at hisswitch, through the substation apparatus, and thence by way of thenormal contacts of springs 22, the inner upper armature of cutoff relay20 and its back contact and the lower winding of relay 19 to ground.Line relay 19 is energized and completes a circuit from groundedbattery, winding of stepping magnet 9, armature and back contact ofmagnet 9, contacts 23 in their normal position, the armature and frontcontact of relay 19 toground. This is a self-interrupting circuit forcontrolling stepping magnet 9, which causes the contactoperatingelements to be advanced until the operating elements 11 and 12 engageand operate a set of contact springs associated with an outgoing linewhich is in a selectable condition. As soon as this occurs, the springs21, 22, 23, 24 and 29, associated with such line are thrown intoengagement with their working contacts.

If it be assumed that thetrunk seized is the one leading to the selectorswitch, whose brushes are indicated at 25, 26 and 27, it is obvious thatas soon as the spring 24 engages its working contact, a circuit iscompleted from ground through the working contact of spring 2 1- overconductor 28 and thence by way of multiples at the other subscribersline switches throughthemagnets 15 at such line switches to groundedbattery. The magnets 15 at such other switches will therefore beenergized to draw the contact sets down out of the path of the contactoperating elements so that when the subscribers to which such switchesare individual, initiate calls the line cannot be ductors of the trunkseized. a

As soon as spring 23 opens its normal contact, the driving circuit ofstepping magnet 9 is openedand the contact-operating elements arebrought to rest in a position to keep the various contact springsinengagement with their working contacts. As soon as the trunk isseized, a circuit is completed from ground through the winding of cutoffrelay 20 and thence by way of the spring .29 and its working contactover conductor 30 through apparatus of any well-known type associatedwith the trunk seized, to grounded battery. Gutofli' relay 20 isenergized in this circuit and removes the control of line relay 19 fromthe calling subscriber in the well-known manner. When conversation iscompleted, the circuit of cutofi relay 20 is broken in any desired,well-known manner and this relay deenergizes. A circuit is thencompleted from grounded battery, winding of stepping magnet 9, armatureand back contact of magnet 9 through springs 23 and their normalcontacts at contact sets other than the one associated with the trunkwhich has been seized, thence by way of the actuated spring 23 and itsworking contact over conductor 31, lower armature and back contact ofcutoff relay 20, also armature and back contact of relay 19 to ground.The contact operating elements are advanced one step in this circuit,thus allowing the contact springs to return to their normal position. Assoon as spring 23 leaves its working contact, the circuit of magnet 9 isopened. As previously described, this step, upon completion ofconversation, operates to bring another arm and its associated contactoperating elements into such a position that one step will bring it intoengagement with the contact set of one of the outgoing lines, providedthat such outgoing line is idle.

What is claimed is:

1. In an automatic switch, a plurality of circuit closers, a pluralityof operating members in fixed relation to one another, a drivingmechanism common to said members, and means to bring said memberssuccessively into operative relation with said circuit closers.

2. In an automatic switch, a plurality of circuits to be tested, aplurality of testing members, means to cause one of said members to makea test, and means to cause each of the other of said members to make atest of other circuits before said first member makes its second test,regardless of the position of said first member whensaid test. was made,i 1

3. In an automatic switch, a plurality of circuit'closers-arranged inthe: arc of a circle, a plurality of rotatable members in fixed angularrelation to one another and inoperative relation to {said circuitclosers, stepby-step mechanism to control the advance of said members,means to advance a given one of said members from 'one of said circuitclosers to the next as a result of a'plurality of steps by saidstep-by-step mechanism, and means to bring said'mem'bers successivelyinto operative relation with said circuit closers. y

4:. In an automatic switch, a plurality of circuit closers, a pluralityof operating mem bers in fixed relation to one another, drivingmechanism for said members, means to bring one of said members intooperative relation with one of said circuit closers, means to advancesaid operating member toward the next adjacent circuit closer, and meansto bring each of the other operating members into operative relationwith others of said circuit closers before said first member is broughtinto operative relation with said next adjacent circuit closer.

5. In an automatic switch, an incoming line, a plurality of outgoinglines, a mechanically operable contact set individual to each of saidoutgoing lines, a plurality of contact operating members in fixedrelation to one another arranged for rotary motion, means to establishconnection between an incoming line and an outgoing line upon operationof one of said contact sets as a result of engagement by one of saidmovable contact-operating members, and means to remove said contact setsfrom the path of said operating members when the outgoing lines withwhich they are associated are in a certain condition.

6. In an automatic switch, an incoming line, a plurality of outgoinglines, a mechanically operable contact set individual to each of saidoutgoing lines, ,a plurality of movable contact-operating members infixed relation to one-another, means to establish a connection betweenan incoming line and an outgoing line upon operation of one of saidcontact sets as a result of engagement by one of said movablecontact-operating members, and means to remove said contact sets fromthe path of said operating members when the outgoing lines with whichthey are associated are in a certain condition.

7. In an automatic switch, an incoming line, a plurality of outgoinglines, a plurality of circuit closers arranged in the arc of a circle, aplurality of rotatable members in fixed angular relation to one anotherand in operative relation to said circuit closers, means to operate acircuit closer when engaged by one of said members to establish aconnection between said incoming line and an outgoing line, means todisengage said operating member from said circuits closer whenconnection is no longer desired, and means to remove said contact setsfrom the path of said operating members whenthe outgoing lines withwhich they are'associated are in a certain condition. o

8.- In, an automatic switch, an incoming line, a plurality of outgoinglines, a circuit closer individual to each of said outgoing lines, saidcircuit closers being arranged in the arc of a circle, a plurality ofrotatable members in fixed angular relation to one another and inoperative relation to said circuit closers, means to advance saidmembers in a step-by-step movement, means to re-' closer when engaged byone of said members to establish connection between said incoming lineand an outgoing line, means to advance said member one step to releasesaid circuit closer when connection is no longer desired, and means toadvance another one of said members as a result of said step into such aposition that a single subsequent step will cause it to engage a circuitcloser, provided the line with which said circuit closer is associatedis in a certain condition.

In witness whereof, I hereunto subscribe my name this 7th day of May, A.D. 1919. GEORGE THOMPSON.

